StringScanner is a simple string tokenizer that provides for lexical scanning operations on a string. It's a JavaScript port of the Ruby library with the same name.

Scanning a string means keeping track of and advancing a position (a zero-based index into the source string) and matching regular expressions against the portion of the source string after the position.

This code is a port of Sam Stephenson's original CoffeeScript version.

Quick start

$ yarn add strscan-ts
$ node

> { StringScanner } = require("strscan-ts")
> s = new StringScanner("This is a test")
> s.scan(/\w+/)             # => "This"
> s.scan(/\w+/)             # => null
> s.scan(/\s+/)             # => " "
> s.scan(/\s+/)             # => null
> s.scan(/\w+/)             # => "is"
> s.hasTerminated()         # => false
> s.scan(/\s+/)             # => " "
> s.scan(/(\w+)\s+(\w+)/)   # => "a test"
> s.getMatch()              # => "a test"
> s.getCapture(0)           # => "a"
> s.getCapture(1)           # => "test"
> s.hasTerminated()         # => true

Slower start

Go get a hot drink, put on some soothing music, visualize your happy place, and delight in the docs.

Information

This is a derivative work of Sam Stevphenson's original.

It is made available under the MIT license.

Copyright © 2022 Dave Thomas